Mechanical Properties of Interlocking Cell Structure for Soft Exoskeleton Suits

Abstract This paper presents design considerations of an adjustable flexible auxetic structure used in soft wearable suits with a Cross Chiral Honeycomb (CCH) structure. In order to design a macro-auxetic structure with elastic flexibilities in the soft wearable suit, it is important to develop an auxetic unit cell with adjustability of stiffness. Airbag inflation and deflation mechanisms on the adjustable stiffness pads with auxetic foam play key roles in either the protection of the human body or the assistance of human motion through the reversible configurations of the structure. Periodic cellular structures used in auxetic foam were first considered in the field of lightweight construction due to their high specific stiffness, damping, and energy absorbing properties. The development of new manufacturing processes, especially the development of modern 3D-printers, has allowed the creation of 3D auxetic structures. Experiments of several specimens were conducted to verify mechanical structural characteristics of a CCH structure. Through this approach, valid geometric parameters of the macro-auxetic structure used in the soft wearable suit could be designated.